Divided tool cutter head have torque yielding coupling

ABSTRACT

A cutting tool shaft is mounted in the free end portion of a jib arm and has a shaft end portion protruding from the free end portion of the jib arm. A cutting tool is carried by said shaft end portion. Torque-limiting clutch means connect said cutting tool to said shaft.

United States Patent [191 Sigott [451 Sept. 10,1974

1 1 DIVIIDED TOOL CUTTER HEAD HAVE TORQUE YIELDING COUPLING [75] Inventor: Siegfried Sigott, Ze1tweg, Austria [73] Assignee: Vereinigte Osterreichische Eisen-und Stahlwerke-Alpine Montan Aktiengeseiischaft, Vienna, Austria [22] Filed: June 28, 11973 [21] Appl. No.: 374,386

[30] Foreign Application Priority Data June 30, 1972 Austria 5641/72 [52] 11.8. C1. 299/85, 64/30 E, 299/89 [51] Int. Cl. E211c 27/24 [58] Fiehil of Search 299/85-90,

299/72-76; 64/30 R, 30 E, 30 A; 175/91 [56] References Cited UNITED STATES PATENTS 1,148,975 8/1915 Kuhn et a1.

1,554,755 9/1925 Parsons 64/30 E 2,695,164 11/1954 Arentzen 1 299/89 X 2,760,800 8/1956 Wekeman 64/30 R X 3,693,734 9/1972 Richmond 299/90 X Primary Examiner-Ernest R. Purser Attorney, Agent, or Firm-Ho1man & Stern [57 ABSTRACT A cutting tool shaft is mounted in the free end portion of a jib arm and has a shaft end portion protruding from the free end portion of the: jib arm. A cutting tool is carried by said shaft end portion. Torquelimiting clutch means connect said cutting tool to said shaft.

5 Claims, 2 Drawing Figures DIVIDIED TOUL CUTTER IHIIEAD HAVE TORQUE YIELDING COUPLING In case of a constant depth of cut of the cutting teeth, a change in the nature of the rock at the face will result in a change of the load on the drive means. The cutting machine will be blocked if the resistance presented by the rock at the face exceeds the driving force. As the time in which the tools are braked is decreased, there will be an increase of the force which is due to the flywheel effect of the rotating masses of the drive means and a resulting increase of the load on the struc tural elements of the drive means. In a limiting case, the load becomes infinitely large in case of a blocking after zero retarding time. The structural parts of the drive means will break if their load-carrying capacity is ex ceeded by the forces which are exerted thereon by the rotational energy which is released in case of a blocking. In cutting operations, particularly in dividing cutting operations, a blocking cannot be avoided and the braking time may be of any order of magnitude. The load peaks must be reduced in order to avoid an overload which would break structural parts of the drive means.

The invention relates to such dividing cutting machine in which cutting tool means are mounted on one or two output shaft end portions at the end of a jib arm, and it is an object of the invention to avoid the disadvantages which are due to an overload. The invention resides essentially in that the cutting tool means are connected to the cutting tool shaft by a torque-limiting clutch, which frictionally transmits torques to a predetermined value whereas in case of an overload due to a blocking of the cutting tool means the shaft end portions slip relative to the cutting tool means.

This torque-limiting clutch may comprise radially preloaded slip clutches or friction elements, which are known per se, because it is only essential that the torque-limiting clutch is provided between the output shaft end portions of the transmission and the cutting tool means.

If the cutting tool means comprise two cutting tools carried by a transmission output shaft which extends transversely to the longitudinal axis of the jib arm, it will be desirable in accordance with the invention to connect each cutting tool by a torque-limiting clutch to the associated output shaft end portion of the transmission.

An embodiment of the invention is shown diagrammatically and by way of example on the accompanying drawing, in which FIG. 1 is a top plan view showing the jib arm of a dividing cutting machine provided with two cutting tools.

FIG. 2 is an axial sectional view showing one cutting tool.

The jib arm 1 is mounted on the cutting machine by a rotating mechanism for pivotal movement in all directions. A cutting tool drive motor may be accommodated in the jib arm 1. At the free end 2 of the jib arm, a cutting tool shaft or transmission output shaft 3 is mounted, which extends transversely to the longitudinal axis of the jib arm and is driven by the cutting tool motor through the intermediary of transmission stages. This cutting tool shaft 3 has two opposite end portions which protrude from the free end of the jib arm. Each of said shaft end portions carries a cutting tool 4, which is connected to the shaft end portion 3 by a torquelimiting clutch 5.

The cutting tool 4 and the torque-limiting clutch 5 are shown on a larger scale in FIG. 2. This torquelimiting clutch 5 consists of one or more slip clutch elements 6, in the embodiment shown by way of example on the drawing of three such elements. Each of these slip clutch elements comprises a biconical outer split ring 7, which cooperates with the bore 8 of the cutting tool 4, and a biconical inner split ring 9, which cooperates with the shaft end portion 3. Wedge-shaped elements 10 and Ill cooperate with these biconical rings 7 and 9 and may also consist of the conical rings. By means of screws 12, the wedge-shaped elements 10 and Ill are forced toward each other to force the biconical split rings 7 and 9 against the bore 8 and the shaft end portion 3, respectively.

The cutting tools 4 are set with cutter bits 13 around their periphery.

What I claim is:

l. A divided tool cutting machine, which comprises a jib arm having a free end portion,

a cutting tool shaft mounted in said free end portion and having a shaft end portion protruding from said free end portion of said jib arm,

a cutting tool carried by said shaft end portion, and

torque-limiting clutch means connecting said cutting tool to said shaft. 2. A divided tool cutting machine as set forth in claim 1, in which said cutting tool shaft has two shaft end portions protruding from said free end portions of said jib arm,

each of said shaft end portions carries a cutting tool,

and

said torque-limiting clutch means connect said cutting tools to said shaft.

3. A divided tool cutting machine as set forth in claim 2, in which said cutting tool shaft extends transversely to the longitudinal direction of said jib arm and said torque-limiting clutch means comprise two torque limiting clutches, each of which connects one of said cutting tools to said shaft.

4. A divided tool cutting machine as set forth in claim 11, in which said torque-limiting clutch means are arranged to transmit torques up to a predetermined upper limit from said shaft to said cutting tool and to slip in response to torques exceeding said upper limit.

5. A divided tool cutting machine as set forth in claim 1, in which said torque-limiting clutch means comprise radially preloaded friction elements. 

1. A divided tool cutting machine, which comprises a jib arm having a free end portion, a cutting tool shaft mounted in said free end portion and having a shaft end portion protruding from said free end portion of said jib arm, a cutting tool carried by said shaft end portion, and torque-limiting clutch means connecting said cutting tool to said shaft.
 2. A divided tool cutting machine as set forth in claim 1, in which said cutting tool shaft has two shaft end portions protruding from said free end portions of said jib arm, each of said shaft end portions carries a cutting tool, and said torque-limiting clutch means connect said cutting tools to said shaft.
 3. A divided tool cutting machine as set forth in claim 2, in which said cutting tool shaft extends transversely to the longitudinal direction of said jib arm and said torque-limiting clutch means comprise two torque limiting clutches, each of which connects one of said cutting tools to said shaft.
 4. A divided tool cutting machine as set forth in claim 1, in which said torque-limiting clutch means are arranged to transmit torques up to a predetermined upper limit from said shaft to said cutting tool and to slip in response to torques exceeding said upper limit.
 5. A divided tool cutting machine as set forth in claim 1, in which said torque-limiting clutch means comprise radially preloaded friction elements. 